Hi byron & djbob! Sorry for my slow follow-up, but thanks for the help. Yes, it's working now.
I didn't think of that for the RewriteCond line -- I guess I was too focused on the RewriteRule's! :-P
Nonetheless, I'm not sure why the rewrite rule lines given before -- which separately consider both names -- didn't work for our www. name. But now they do -- just tried. (Please see those below.) Did you do something else besides remove the caret, djbob?
BTW... I guess you know that cPanel's management of rewrite rules in our main .htaccess file -- at least where Ruby and your proxy server are concerned -- really seems to suck. Even aside from the placement of rules that didn't work, it would add rules at the ending of other lines -- breaking the file! -- nor would it actually delete rules previously added when commanded to do so. My only resort was to hand-edit. Perhaps my experience is not the norm; but if not, I'd sure like to know why.
Thanks again for your help, and TIA for any comments on the above.
Following, for byron's sake ;-) and for reference to the above, are my rewrite lines, with commented-out lines I had tried earlier. (I replaced for this post the actual app/proxy port number with "NNNNN".)
Cheers,
-cba
======================================================
RewriteCond %{HTTP_HOST} chorusbreviarii.org$
RewriteRule .* "http\:\/\/127\.0\.0\.1\:NNNNN%{REQUEST_URI}" [P,L]
#############################################################################
#
# This is the style of rule spit out by cPanel. It works... barely.
# Images and style elements are missing. (?)
#
# RewriteRule ^/?$ "http\:\/\/127\.0\.0\.1\:NNNNN%{REQUEST_URI}" [P,QSA,L]
#
#
# Before, these would work for chorusbreviarii.org, but not for
# www.chorusbreviarii.org ... Now they work for both. (?)
#
# RewriteCond %{HTTP_HOST} ^chorusbreviarii.org$
# RewriteRule .* "http\:\/\/127\.0\.0\.1\:NNNNN%{REQUEST_URI}" [P]
#
# RewriteCond %{HTTP_HOST} ^www.chorusbreviarii.org$
# RewriteRule .* "http\:\/\/127\.0\.0\.1\:NNNNN%{REQUEST_URI}" [P,L]
# RewriteCond %{HTTP_HOST} ^chorusbreviarii.org$ [OR]
# RewriteCond %{HTTP_HOST} ^www.chorusbreviarii.org$
# RewriteRule .* "http\:\/\/127\.0\.0\.1\:NNNNN%{REQUEST_URI}" [P,L]
======================================================