Chateau du Prince Leopold

On Saturday and Sunday while coming back from our treks through the woods we passed this intriguing building which stands along the outer ring road around Brussels between Groenendaal and Jezus-Eik on the outer edge of Hoeilaart. The decoration on its side says it's the "Chateau du Prince Leopold". I went back today to take a picture while the weather was still good. It's very difficult to find more information about it, been Googling in three languages, but haven't found much. It used to be a hotel and a restaurant as many old postcards show and it is nowadays in use as a private carehome for the elderly. On their website it says this building used to be the hunting lodge for Prince Leopold (I presume of Belgium), but which one, as there were at least three who had that name and were once princes? I will have to find out more :-)