Here's how I might have done that. I've accounted for elements with embedded and terminal newlines. This also prints a final newline if the last element didn't end with one.

#!/usr/bin/env perl

use strict;
use warnings;

my $delimiter = '<TAB>';
my @info = (1 .. 5, "\n", 6 .. 10, "\n", "A\nB", "C\n", 'D', 'end');

print /\n$/ ? $_ : "$_$delimiter" for @info[0 .. $#info - 1];
print $info[-1] =~ /\n$/ ? $info[-1] : "$info[-1]\n";
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Output:

1<TAB>2<TAB>3<TAB>4<TAB>5<TAB>
6<TAB>7<TAB>8<TAB>9<TAB>10<TAB>
A
B<TAB>C
D<TAB>end
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[Obviously, <TAB> is just used as a visual aid: change '<TAB>' to "\t" in the real application.]

Update: Changed "'<TAB>' to "\n"" to "'<TAB>' to "\t"". Thanks to Laurent_R for spotting that.