[robotresearcher]

A sidebar issue: all these rules apply to knighthoods from the UK crown only. And under these rules non-Brits may be knighted but do not use the title 'sir'. Thus Bill Gates KBE is not known as Sir Bill.

(edit: Today I learned that Kazuo Ishiguro is British. The statement below is completely wrong. I've managed to get his nationality wrong while enjoying his books for 20 years!)

So in the specific case of Kazuo Ishiguro, the sir does not apply. For Brits with family-first names, see the other answers.

[DanBC]

Kazuo Ishiguro is British. He's not called "Sir" because he has an OBE. He needs a GBE or DBE for the "Sir".

https://en.wikipedia.org/wiki/Order_of_the_British_Empire

[OJFord]

And were he not British, he would not be entitled as such - Gates and Geldof iirc are such examples; sometimes (incorrectly) titled 'Sir' in press.