It's a pity Eddie is a former friend
Just in case anyone else is reading "erstwhile" as the old dictionary definition, I stress that in this case I'm using it in the modern colloquial form meaning longstanding.

Eddie and I are still good friends after over ten years of collaborating!
Interesting, I know I'm old but I've not known "erstwhile" as anything other than in keeping with the "old' definition...it seems most online dictionaries agree - the internet must be older than I thought.
Modern, colloquial could be ex or past I suppose.
Most importantly Electric Eddie is current and currently singing well.