I can hardly imagine any reason why HRC would be interested in Lorenzo.
Pedro is the perfect teammate to Marquez. They've got a long list of young candidates to take Pedro's seat when they need to start thinking beyond Marquez, but right now, they don't.
HRC is the favorite to win the championship through 2020. It ain't broke, I doubt they will try fixing it.
If I were Lorenzo, I would negotiate a new performance based contract with Ducati with a low base. At least he will remain on a factory team and give himself more time to learn and adapt. Problem is, it sounds like Ducati and company aren't too keen on keeping him around, and they need to consider the risk of losing their young talent in Miller and Petrux.
JLo isn't going to leave MotoGP, but IMO, he's either on the Ducati or on a satellite Yamaha next year.