A classic Japanese song!

The lyrics you provided are:

「ガールは忘れたころにやってくる」

Translated to English, it would be:

"The girl who comes back when she's forgotten"

This is a famous phrase from the song "Girl" by Yumi Arai (also known as Yumi Matsutoya), released in 1976. The song is about a woman who is forgotten by her lover after their relationship ends, but she still holds on to the memories of their time together and continues to appear in his life like a ghost.

The song became a huge hit in Japan and is often considered one of the greatest Japanese songs of all time. It's known for its hauntingly beautiful melody and poignant lyrics that capture the bittersweet emotions of lost love.