Tracy- My thinking is that even if this is osmotic diarrhea and is he growing well, staying hydrated and not having any other problems like cramping/pain or bad diaper rash (from having a wet bottom all the time), then there would be no reason to take him off Elecare. Osmotic diarrhea does not necessarily equate with malabsorption.
I’d talk to the ped or ped GI- here is another way of looking at this… if other things have been ruled out, maybe this is just osmotic diarrhea and requires no treatment at all (other than investing in some highly absorbent diapers with snug leg elastic).