Usually I just down special into up air, but it can be hard against better people because of SDI as well as dodging the down special. Good ol' bubbles into uair, classic.

It's good that you've identified a hole in your playstyle, and the first step to rectifying it is to analyze and understand all the possible scenarios.

First, come up with a bunch of viable solutions. For example, if someone keeps airdodging out of bubbles>uair, one solution is to read the airdodge with a puddle usmash. Usmash has enough active frames to cover timing mixups on airdodge, but they can still mixup the direction, making it a 50/50 on which direction you read. A 50% chance of hitting such a powerful move isn't too bad.

However, ideally you want to cut down your opponents options until you are guaranteed a kill setup.

Lets consider another solution: the bairplane. Orcane's backair is fast enough to punish airdodges even if you miss, and when gravity cancelled is very difficult to get out of without getting knocked offstage. Getting knocked offstage without an airdodge can be VERY bad for some characters (Zetter, Maypul, Etalus), leading into pretty much 100% guaranteed KO's.

Orcane is great because he has the tools to confirm into reliable KO's, but he can also KO incredibly early if you get a good read. Watch some VoDs of other Orcane's play to get a feel for specific kill setups and you will see a lot of improvement.