This won't work on bosses that one shot or close to one shot you, but if you spec arcane and especially of you have any of the legendaries that give extra barriers, just spam prismatic barrier, dot the elite with nether tempest and kit it around. If you stand still and free cast you will do more damage but the elites will typically break through the barriers, even alternating with casts and barriers on gcd, so to be safer it would be best to kill them slowly.
I had to rely on this in one of the invasion points, just me to take out some 300K plus elite, not enough damage in frost to burn him down fast enough, but with arcane, wittle him down and win. You can of course fire off arcane barrages while on the run as well, and that gives you some speed to delay elites catching you and swatting your barrier.
What was once impossible to solo, is now possible for I'd say most elites that are immune to cc and not too op.