They can't -- The Lone Ranger and The Green Hornet are two different properties and ended up in separate hands many years ago.
If at some point in the future someone manages to acquire both properties then the connection could be used. But for now, at the most, all there might be is a very general reference -- nothing that, by itself, would necessarily "say" Lone Ranger. Now Comics got away with a stronger reference but that was in a comic book, the movie will have much higher profile so the lawyers are probably watching it more closely.