If the ball rebounded off Lovren then Kane should have been called offside. If Lovren played the ball then Kane was onside. I think attempting to block a shot or a pass counts as rebound. I didn't see this incident yesterday though so I don't know if it was offside or not.
https://www.youtube.com/watch?v=UzTJ0K-eLZM That's a link to the next penalty. I don't think VAR would have called it. Simply touching another player isn't a foul. A challenge / tackle should be made in a manner considered by the referee to be careless, reckless or using excessive force. Also the ref saw it and didn't call for penalty..