You could throw in Season 9 as well, considering that Nine’s rights to the season had apparently expired, and will air on Foxtel’s Comedy Channel from next weekend.
If Nine are not airing Season 11 the week after the Season 10 finale airs, then there’s also the possibility that they haven’t bought the rights, and therefore may end up somewhere else, such as Stan (as mentioned above) or possibly even Ten after CBS takes ownership of the network (yes, I know TBBT is not a CBS-produced show, but it airs on the network in the US).