use strict;
use warnings;

sub printdata {
		my $data = shift;
		$$data{"User-Agent"} //= "--";
		print join "|", @$data{ ( "Arrival Time", "From", "To", "User-Agent" ) };
		print "\n\n";
		%$data = ();
}

my %data;
my ($item, $value);
print "Arrival Time|From|To|User-Agent\n\n";
while(<DATA>){
		chomp;
		next unless ($item, $value) = /^(.*?): (.*)/;
		printdata \%data if $item eq "Arrival Time" and %data;
		$data{$item} = $value;
}
printdata \%data;

__DATA__
Arrival Time: May 2, 2013 10:37:50.813000000
...