l function converts automatically system path in alias where available.
This simple snippet ports this useful function on your raw HTML attributes, point to alias or to the system path.
if(($nodepath = drupal_lookup_path('alias',"node/".$realnode->nid))===FALSE)
$nodepath = base_path() . "node/".$realnode->nid;
Where $nodepath can be used on href
Cfr. drupal_lookup_path
chirale 