Well just of the top of my head and a verry quik look at wikipedia
n Norse polytheism, Thor (from Old Norse Þórr) is a hammer-wielding god associated with thunder, lightning, storms, oak trees, strength, destruction, fertility, healing, and the protection of mankind.
Id define the theme of this kind of sponsored magic as the above. Though i would recommend cutting it down to thunder, lightning, storms, and strength, as healing is problematic in the dresdenverse, destruction is slightly redundant and i personally am not aware of any myths of thor that involve him being depicted as a god of fertility.
That gives you the basis of your rituals and channeling, which using the system farther back in this thread is 2 of the four points you get to allocate.
# Access to Rituals for the sponsor's theme [1]
# Access to Channeling for sponsor's element [1]
Personally for the other 2 i would probably choose
Reducing the effectiveness of all creature’s toughness powers [2]
As the Norse god whose domain it is to protect mankind i would give his magic the same ability to bypass toughness/recovery that soulfire gets. If that doesn't sit well with you id go with +1 to the power, control and +2 complexity to all of your thunder/lightning evocations.