He started training with Luke. From WGA script:
There was nothing we could've done.
(hard for him to say)
There was too much Vader in him.
That's why I wanted him to train with Luke.
I just never should have sent him away.
That's when I lost him. That's when I lost you both.
In addition, in the Novelization, Snoke explicitly discusses with Kylo Ren that he sculpted him BASED on his training with Luke.
"It is your teachings that make me strong, Supreme Leader"
Snoke demurred. "It is far more than that. It is where you are from. What you are made of. The dark side--and the light. The finest sculptor cannot fashion a masterpiece from poor materials. He must have something pure, something strong, something unbreakable, with which to work. I have--you"
Further confirmation from TFA Visual Dictionary:
Having studied Jedi skills as well as arcane dark side lore...
and his training with Snoke is mentioned as well:
Kylo Ren is the most gifted apprentice of Supreme Leader Snoke... (of course, we can also see the same from film dialog)