Plasma casters only locked on in AvP and the other Pred movies. They didnt home in or anything, so it can be dodged. Its hard to say if Cage can withstand the blades from an Elder, however. Les remember, the metals they use arent like any from Earth. For all we know, it can be as tough as titanium, vibranium or adamantium. And Tassadar is right. Saying normal weapons is to general. Some Elders dont carry energy weapons at all. Some do. Id give the Elder the slight edge either way.