Doesn't matter if it's thrown. I always thought the expression was "leading with the elbow" which is exactly what he did.
No he didn't, and yes it 100% does matter, It is difference between violent conduct (which throwing the elbow with force is, and is a straight red) and playing in a dangerous/reckless manner which placing a forearm against an opponents cheek could be considered as, which is a cautionable offence.