my %hash;
for(@ARGV)
{
  my($key,$val) = split/=/,$_,2;
  $hash{$key}=$val;
}

use Data::Dumper;
print Dumper(\%hash);

__END__
Output:

$VAR1 = {
          'vchtyp' => 'I',
          'jrnltyp' => 'D',
          'title' => '\'this is a title\'',
          'lexwhere' => '\'in(\'DIS\', \'DIM\', \'DIR\')\''
        };
(Data::Dumper is inserting those extraneous backslashes, ignore them)