php – HTML Special Characters in URL string

I am using this code to convert the & to its html entity but it doesn’t work. The output is passed to a field in gravity forms.

<a href="http://wordpress.stackexchange.com/enquiry/?event=<?php $urlst=get_field('fl_name');htmlspecialchars($urlst, ENT_QUOTES);echo $urlst; ?>">Make a request</a>

If I have fl_name= Music & TV Shows then in my gravity forms output i only see Music