にいたころ

when (someone) was in

→ に
phrase Rare #39,629
when (someone) was in Follows a place and refers to the time someone was there.
JA: 京都にいたころ、よくお寺を訪れました。
EN: When I was in Kyoto, I often visited temples.

彼女はロンドンにいたころよくその劇場に行ったものだ。

She used to often go to that theater when she lived in London.

私たちはアメリカにいたころ日曜日ごとに教会へ行った。

When we were in America, we went to church every Sunday.

ジャングルにいたころにゃあのキムにだって分かってたはずなのにな

Even Kim must have known that back when we were in the jungle.

— イノセンス (2004)