Load the irelia script that you like, then go on "combo setting" and make sure Q is marked.
I don't know why, but a lot of scripts are with they combo skill list unmarked.
I was testing, the Q is only activated when you attack the enemy, that is, only when doing the combo will it be done automatically. You can also use it manually, it's not too difficult as it marks you with a green circle when you can.
You need to do some things manually to have better combos, but I believe that LB today is already much better for me.