If you are looking at your "Total reward:", remember that it is a combination of your "Confirmed reward" (that which has already been confirmed) and your "Unconfirmed reward" (that which is yet to be confirmed). If a block is "Orphaned" in the process of getting all its confirmations, then it is no longer considered a part of the "Unconfirmed reward" and is then not considered in the "Total reward", so yes, it is subtracted from the "Total reward". Effectively, the "Total reward" is what you will bank if each of the pending blocks is "confirmed". The only money that you actually have in the bank is the "Confirmed reward" and that value doesn't change if a pending block is determined invalid.