There's really two parts to the question: are T-tails more susceptible to ice accretion; and are T-tails more sensitive to ice accretion.
For the first question, a T-tail would appear to be completely 'unshadowed' while there is a small amount of geometrical shadowing possible for a low-mounted tail, due to it being behind the wing. This effect is probably relatively minor, though.
Also, one might expect, all other things being equal, that a T-tail may be slightly smaller than a low-tail, which would tend to make it a better ice catcher. (On a swept fin, a T-tail may be slightly further aft, allowing a smaller area for the same tail volume, plus the fflow field at the top of the fin may allow a smaller tail for the same effect; countering these somewhat, a T-tail aircraft often has a shorter fuselage aft of the wing - due to the engine effect on cg - than a low tail aircraft, which would cause the T-tail to be larger in that case.) My own guess is that the T-tail ends up being slightly smaller overall from these effects, but I doubt it is a big factor.
In terms of sensitivity, again the size of the tail will have an effect (smaller surfaces being more impacted by a given ice catch) so any tendency for a smaller size will have an effect here also. I doubt if there's any other systematic design effect that would heighten sensitivity of either design.