Or, if you're not stuck on using just $dbh->selectall_arrayref and your database supports placeholders, couldn' you do this?

$sth = $dbh->prepare("SELECT " . '? ' x $#selector . "FROM people WHER
+E (fornavn LIKE '%$search%') or (eternavn LIKE '%$search%') or (cpr L
+IKE '%$search%'", \%attr); #dunno if you can do the \%attr part...
$sth->execute(@selector);
[download]

And then you've got a statement handle to get your data from.. I don't know if it's more efficient, but it seems a bit more readable to me.