\nopagebreak after a center environment

Question

I have the following code for a Theater play. Sometime the page breaks just after the name of a character. I would like to avoid that. I would be good if I could do it only by modifying the command \character since the play is 200 pages long with many different characters. I tried to use \nopagebreak but I was not successful. What can I do in order to never have the name of a character on the bottom of a page?

\documentclass[a5paper]{book}
\usepackage{geometry}
\usepackage{lipsum}

\newcommand{\character}[1]{
  \begin{center}
    \textsc{#1}
  \end{center}}

\begin{document}
  \character{Alice} \lipsum[2]
  \character{Bob} \lipsum[2]
  \character{Charles} \lipsum[2]
  \character{David} \lipsum[2]
  \character{Edmond} \lipsum[2]
  \character{Francis} \lipsum[2]
\end{document}

Answer 1

latex headings include code to prevent a page break until a couple of lines after a heading, so it best to define this as an unnumbered heading:

\documentclass[a5paper]{book}
\usepackage{geometry}
\usepackage{lipsum}

\makeatletter
\newcommand{\character}{%
 \@startsection {section}{1}{\z@}%
                                   {-3.5ex \@plus -1ex \@minus -.2ex}%
                                   {2.3ex \@plus.2ex}%
                                   {\normalfont\scshape\centering}*}
\makeatother

\begin{document}
  \character{Alice} \lipsum[2]
  \character{Bob} \lipsum[2]
  \character{Charles} \lipsum[2]%aaa\\bb
  \character{David} \lipsum[2]
  \character{Edmond} \lipsum[2]
  \character{Francis} \lipsum[2]
\end{document}

Answer 2

Add \vfil before the center environment in your command:

\documentclass[a5paper]{book}
\usepackage{geometry}
\usepackage{lipsum}

\newcommand{\character}[1]{%
  \vfil
  \begin{center}
    \textsc{#1}
  \end{center}
}

\begin{document}
  \character{Alice} \lipsum[2]
  \character{Bob} \lipsum[2]
  \character{Charles} \lipsum[2]
  \character{David} \lipsum[2]
  \character{Edmond} \lipsum[2]
  \character{Francis} \lipsum[2]
\end{document}

Output

Addendum

You can also wrap the character name and his words together into a \vbox to prevent that they get separated. But, for that you would need to change every single call of the character macro. (I added it just for completeness for future users who are interested in typesetting theater plays and encounter a similar problem.)

\documentclass[a5paper]{book}
\usepackage{geometry}
\usepackage{lipsum}

\newcommand{\character}[2]{%
  \par\vspace{1em}
  \vbox{%
    \par\hfil\textsc{#1}\hfil
    \par\vspace{1em}
    \par#2
  }
}

\begin{document}
  \character{Alice}{\lipsum[2]}
  \character{Bob}{\lipsum[2]}
  \character{Charles}{\lipsum[2]}
  \character{David}{\lipsum[2]}
  \character{Edmond}{\lipsum[2]}
  \character{Francis}{\lipsum[2]}
\end{document}

_{Note: The output is almost as above.}