Yes, the quote
"An artist's concern is to capture beauty wherever he finds it" is indeed part of Kazuo Ishiguro's novel "An Artist of the Floating World".
This quote is preceded by the quote "
Forgive me, Matsuda, but it strikes me it's you who are in fact the naïve one." and is followed by the quote:
"But however skilfully he may come to do this, he will have little influence on the sort of matters you talk of. Indeed, if the Okada-Shingen is as you claim it is, then it seems to me ill-conceived indeed. It seems to be founded on a naïve mistake about what art can and cannot do."
I hope this helps!