Question: what to do after you beat lysandre in pokemon y?
Answer: Battle Lysandre. As soon as you go up the stairs, you meet Lysandre, and must battle him. ... 
Explore the Lab. After you defeat Lysandre, he says you have to find the Elevator Key from one of the scientists. ... 
Battle Aliana. ... 
Explore More. ... 
Fight Celosia and Bryony. ... 
Continue Exploring. ... 
Battle Mable. ... 
Use the Elevator.