now that you mention it

宮部みゆきのの小説 "The Devil's Whisper" を読んでいます。

"I have this feeling that your father is upset about all this, too."
Mamoru struggled to hide his surprise. "I feel like he's somewhere close by and that he's been keeping an eye on you and your mother. He knows you're here with the Asanos and he wants to come see you, but he just can't bring himself to."
"Now that you mention it, whenever I've gone to put flowers on my mother's grave on special days, someone has always been there before me--"

"Now that you mention it" この言い回しは英会話の教本によく出てくる台詞で、日本語の「そう言われてみると/そう言えば」に相当するようですが、英英辞書にも用例があるか調べます。

・Wiktionary: Used to precede another comment about something just mentioned.: Everybody gets their own ration of luck, they say. Now you mention it his face was familiar to me.
・TheFreeDictionary: An expression used when one remembers or realizes something because of what the other person has just said.: A: "The weather's been a bit unpredictable lately, huh?" B: "Now you mention it, I hear there could be a blizzard next week."