I would like to align the picture to the top of the text, specifically the line where the text starts (ascender). As you can see, there's still a small gap. How can I remove this space?
\documentclass[a4paper,DIV=15,oneside,12pt]{scrartcl}
\usepackage[english]{babel}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{blindtext}
\usepackage{graphicx}
\usepackage{setspace}
\usepackage{wrapfig}
\parskip 0pt
\parindent 0pt
\begin{document}
\onehalfspacing
\begin{wrapfigure}{r}{4cm}
\centering\rule{3cm}{2cm}
\end{wrapfigure}
\blindtext
\end{document}