Lettrine with paracol – second column problem

Question

I'm using paracol to typeset a book with two columns (facing translation). I'm trying to add drop caps using the lettrine package, but the drop cap in the second column sticks out to the left instead of indenting the text:

I didn't see an obvious parameter in the lettrine documentation that would fix this behavior.

This discussion looks related, but the problem/solution are related to \lettrine being in a list (and thus, essentially inside a paragraph). In my case, we're clearly at the beginning of a new paragraph, so I'm not sure what I'm missing.

Here's the MWE that produces this:

\documentclass[letterpaper,titlepage,twoside,openany,12pt]{book}

\usepackage{paracol} 
\setlength{\columnsep}{30 pt} %more space between the columns

%avoid overfull hbox with narrow columns
\tolerance=400      
\hbadness=399   
\setlength{\emergencystretch}{0.5em}


\usepackage{polyglossia}
\setdefaultlanguage[variant=american]{english}
\setotherlanguages{icelandic,danish,norsk,swedish}

\usepackage{lettrine}
%I don't like the rest of the word being in smallcaps
\renewcommand{\LettrineTextFont}{\normalfont}

\begin{document}

\begin{paracol}{2}

\switchcolumn[0]*
\noindent
    \lettrine[lines=5,loversize=0.1]{O}{nce} upon a time, there was a prince
    who was an only child.  He was so well-known for his intelligence and his
    good looks, that he became quite proud.  Because of his own beauty, he was
    very fond of beautiful things.  But, he could not endure ugliness; he said
    that he found it painful to even look upon something ugly.

\switchcolumn
\begin{danish}
\noindent
    \lettrine[lines=5,loversize=0.1]{D}{er} var engang en Konge, som havde en
    eneste Søn.  Prinsen var bekendt for sin Skønhed og store Forstand.  Men
    han blev ganske hovmodig deraf.  Ligesom han selv var smuk, holdt han meget
    af alt, hvad der var smukt. De grimme kunde han ikke udstå; han fik ganske
    ondt af at se på hvad der var stygt, sagde han.
\unskip
\end{danish}

\end{paracol}

\end{document}

Answer 1

My initial lettrine search of tex.SE somehow failed to turn up this discussion: Why is this lettrine being bumped into the margin

Simply adding a \par at the end of my danish paragraph fixes the problem.

I guess my question now is why is this necessary? What is it about polyglossia's \begin{language} \end{language} environment that prevents lettrine from recognizing the paragraph has ended? (Again, keep in mind that I'm a pretty unsophisticated latex user.) The \unskip itself seems to have nothing to do with it (removing it doesn't solve the problem, leaving it in after \par doesn't cause a problem either).

My new MWE:

\documentclass[letterpaper,titlepage,twoside,openany,12pt]{book}

\usepackage{paracol} 
\setlength{\columnsep}{30 pt} %more space between the columns

%avoid overfull hbox with narrow columns
\tolerance=400      
\hbadness=399   
\setlength{\emergencystretch}{0.5em}


\usepackage{polyglossia}
\setdefaultlanguage[variant=american]{english}
\setotherlanguages{icelandic,danish,norsk,swedish}

\usepackage{lettrine}
%I don't like the rest of the word being in smallcaps
\renewcommand{\LettrineTextFont}{\normalfont}

\begin{document}

\begin{paracol}{2}

\switchcolumn[0]*
    \lettrine[lines=5,loversize=0.1]{O}{nce} upon a time, there was a prince
    who was an only child.  He was so well-known for his intelligence and his
    good looks, that he became quite proud.  Because of his own beauty, he was
    very fond of beautiful things.  But, he could not endure ugliness; he said
    that he found it painful to even look upon something ugly.

\switchcolumn
\begin{danish}
    \lettrine[lines=5,loversize=0.1]{D}{er} var engang en Konge, som havde en
    eneste Søn.  Prinsen var bekendt for sin Skønhed og store Forstand.  Men
    han blev ganske hovmodig deraf.  Ligesom han selv var smuk, holdt han meget
    af alt, hvad der var smukt. De grimme kunde han ikke udstå; han fik ganske
    ondt af at se på hvad der var stygt, sagde han.
    \par
    \unskip
\end{danish}

\end{paracol}

\end{document}

And the result:

Answer 2

I removed your command \unskip in danish part and ended the danish paragraph by the command \. Now I Compiled your code and I got the following.