These are all extremely valid points, I'll agree, but there are many, many factors to a fight between the two. The biggest factor, to me, is whether or not the Elder has its mask.
Predators, without their masks, sense everything solely in infrared, namely on the level which corresponds to body heat. Their natural vision is adapted for much cooler climates that those on Earth, hence why everything appears to be red and orange from the predator's point of view in Predator.
As I continually fall back on time and time again (please correct me if I'm wrong here), xenomorphs do not give off ANY heat signature (hence why they couldn't be detected in Aliens). This is also a large continuity error in AvP, as well as many RPGs which are conducted on this forum.
Because of this, an Elder would be unable to see an Alpha xenomorph without its mask. This, I believe, holds sway to the entire confrontation.
"If anything in this life is certain, if history has taught us anything, it is that you can kill anyone." - Michael Corleone