Dreaded clunk when turning

I think it's time to inspect the Rear U-joint and if that's ok then pop the cover and check the spiders, the cross-pin and the axle splines.
When turning, the outside wheel has to travel a bigger circle.... and that means it has to rotate faster than the inside wheel, ...... and that means a lot of the engine torque is going thru the now-spinning spiders. In the straight-ahead position, they are mostly stationary.
It is odd that it only does it on the left side, so I suppose it could be a wheel-bearing, or even a loose spring mount, or even loose wheel-nuts.
But you'll figure it out in a jiffy.
Tooljunkie could be right too, and since that is the easiest test,(Well except for loose lugnuts), you might as well start there.