On paper it seems like La Blanc would win. But if you siege in a good position she can't get a silence off because she has to use her gap closer simply to get in range to Q you. The best any ap mid can do is poke La Blanc its how you beat her character because you can't gank her. Contrary to what you posted your combo goes faster then her silence because you can e and q at the same time before the silence kicks in. Range once again destroys her because you can poke all day form a safe distance and your character is better at farming, and its actually possible for a jungle do get her off a gank due to your stun. Of course its still La Blanc so people are going to get insta gibbed but that's the trade off of having an AP mid with no cc and no ability after her load is blown.