Since the tax burden on an "equivalent lease" will be the same cost whether you get a Tesla or an Acura that are roughly the same price, we'll call that a wash and disregard it.
Assuming 15k miles of personal use per year (conservative, high end estimate), that's an added tax burden of $187.50 assuming a 25% tax bracket.
Average cost of charging an electric car at home is in the neighborhood of ~$700/year. Since work would be willing to buy your gas for personal use, this will be a cost you bear.
So, $887.50/year. Spread over the 3 year lease, you just need to ask your work for a gross up of $2,662.50 to offset the taxes that are factoring into your decision here.
You might also consider the potential growth of that $2,662.50 if paid as a lump sum at vehicle purchase instead of spread out over the 3 year lease. You come out ahead...