Lastname Prefix not recognised if no first name

[henrysearle]

Input: Vincent Van Gogh
Expected: Vincent van Gogh
Actual: Vincent van Gogh ✅

Input: Mr Vincent Van Gogh
Expected: Mr Vincent van Gogh
Actual: Mr. Vincent van Gogh ✅

Input: Mr Van Gogh
Expected: Mr van Gogh
Actual: Mr. Van Gogh ❌

I would have expected this to be detected as a salutation and lastname.