For what you're defining as your "need ...ATM," is there some problem with the solution offered in Re: search and using first letter of words on a line? It works:

#!/usr/bin/perl
use strict;
use warnings;
# 927275
use 5.012;

my @title = ("Part II: Nietzsche's Project, An Overall Review", "Learn
+ing Perl, 5th Ed.", "Mastering Regular Expressions");
for my $title(@title) {
    my $acronym = join '', ($title =~ /(?:^|\s+)(\w)/g);
    say $acronym;
}

=head OUTPUT

PINPAOR
LP5E
MRE

=cut
[download]

Of course, your spec leaves a little to be desired: how will you distinguish among Parts I, II and III of your first title?

If your problem is in applying that answer to <a href="file:///foobar baz">Bazing with foo</a>, then you need to consider something on the order of HTML::Parser or another of the HTML::... modules.

If you have some other stumbling block in your way, pray detail it, but without teaching Grandmother how to cook eggs with sed.