\hrulefill suddenly disappearing
blockquote
does not indent its argument text, so there's no need for \noindent
. However, to provide a full line of fill, set something (nothing) at the beginning of the line:
\documentclass[12pt]{article}
\usepackage[a4paper]{geometry}
\usepackage{csquotes,lipsum}
\begin{document}
\lipsum[1]
\blockquote{\mbox{}\hrulefill \par
Nam dui ligula, fringilla a, euismod sodales, sollicitudin vel, wisi.
Morbi auctor lorem non justo. Nam lacus libero, pretium at, lobortis
vitae, ultricies et, tellus. Donec aliquet, tortor sed accumsan
bibendum, erat ligula aliquet magna, vitae ornare odio metus a mi.
Morbi ac orci et nisl hendrerit mollis. Suspendisse ut massa. Cras
nec ante. Pellentesque a nulla. Cum sociis natoque penatibus et
magnis dis parturient montes, nascetur ridiculus mus. Aliquam
tincidunt urna. Nulla ullamcorper vestibulum turpis. Pellentesque
cursus luctus mauris.
\\\mbox{}\hrulefill}
\lipsum[3]
\end{document}
If this type of decoration is something you're interested in using more frequently, you could incorporate it in a fixed command, rather than adding horizontal rules manually. It provides consistency. Below is an example that uses a regular tabular
to set the quote (foregoing page breaking, of course):
\documentclass[12pt]{article}
\usepackage[a4paper]{geometry}
\usepackage{lipsum}
\newcommand{\blockquote}[1]{\par\bigskip{%
\centering\begin{tabular}{p{.85\linewidth}}
\hline \\[\dimexpr-\normalbaselineskip+5pt] #1 \\[5pt] \hline
\end{tabular}\par}\bigskip}
\begin{document}
\lipsum[1]
\blockquote{%
Nam dui ligula, fringilla a, euismod sodales, sollicitudin vel, wisi.
Morbi auctor lorem non justo. Nam lacus libero, pretium at, lobortis
vitae, ultricies et, tellus. Donec aliquet, tortor sed accumsan
bibendum, erat ligula aliquet magna, vitae ornare odio metus a mi.
Morbi ac orci et nisl hendrerit mollis. Suspendisse ut massa. Cras
nec ante. Pellentesque a nulla. Cum sociis natoque penatibus et
magnis dis parturient montes, nascetur ridiculus mus. Aliquam
tincidunt urna. Nulla ullamcorper vestibulum turpis. Pellentesque
cursus luctus mauris.}
\lipsum[3]
\end{document}
To allow page breaking of such quotes, one could also consider mdframed
.