Chelsea stopped being Champions once the season started.
We are the current champions as we have won the league. In my eyes we will be champions until the next season kicks off in August.
Then nobody is champions as nobody has won that league season yet.
No-one is ever only champions for the summer - Teams are always referred to as the current champions the following season. Reason being no-one can usurp them with only 10 or 20 games played. We are now the champions, because we've won the league. Chelsea ceased being 'current' champions the minute the whistle was blown at the rags just like we will be the moment someone else wins it instead of us, whatever game that may be.