moss and scarifying lawns

I have read your answer how to get rid of moss, but I have more questions. My garden had lots of trees around it but they have been cut down, so now i need to deal with the ever growing problem of moss:

1. Do i need to areate or scarify the lawn beforehand?

2. Is it a good time to scarify the lawn now or have i left it just that bit late?

Thanks for the advice,

Lorraine