The half a satoshi per block will be lost, and the block reward will go from 0.09765625 BTC to 0.04882812 BTC.

This will happen multiple more times over the rest of bitcoin's future. For example, starting at halving number 13 the reward will progress as follows, losing half a satoshi each time:

0.01220703 BTC
0.00610351 BTC
0.00305175 BTC
0.00152587 BTC
0.00076293 BTC

Because of these cumulative losses, the maximum supply of bitcoin is not 21 million, but rather 20,999,999.97690000. Or at least, it would have been this number if other bitcoin had not been irretrievably lost along the way.