Marc, honey that the bees consume over winter contains some 10% + or -
water.  The bees generate heat to keep themselves and larvae warm, and that
heat causes moisture to condense in the hive.  If sufficient condensation is
present it can kill your bees...which is why ventilation is so important in
the winter.
 
The bees do need water to use the dry sugar.  Moreover, as they begin to
raise larvae in ernest they need more water than they can get from the
honey.  In mid-summer they get lot's of water from nectar, which can be as
much as 99% water.  In the very early spring when nectar sources are poor
(maples, for example, have lot's of pollen but little nectar) bees will
congregate at any "puddle" or water source then can find so they can get
water to dilute the honey to make larvae food.
 
The bees will not do much at all with either the patty or dry sugar (other
than throw it out of the hive) until they can get some water.  However, they
are truly ingenious at finding it so they will as soon as they can fly.