So I think you want a refresher on how two-way players work on Ottoneu lineup and Roster Organizer pages:
You can move Lorenzen into an empty RP slot, but you cannot currently move him into a pitching bench slot - he will live on the hitter bench unless explicitly put into a RP slot. In the thread I linked to, I mention that this is not because of some high-minded logic but because it just made the whole implementation a little cleaner.