Lastname Prefix not recognised if no first name

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.
