1. I only recognized him when he came into light
-> Not until he came into light did I recognize him.
2. John didn't celebrate until he received the offer of promotion in writing.
-> Not until he received the offer of promotion in writing did John celebrate.

1) 

Not until John received the offer of promotion in writing did he celebrate a party
2)

→ It wasn't until John received the offer of promotion in writing that celebrated a party.

1. Not until he came into light did I recognize him.
2. Only when John received the offer of promotion in writing did he celebrate.