[cryvate1284]

In this case, the problem arises, because they are using Mr de Zwart [sic], but can this not by avoided by simply using the full name? Mr Thomas de Zwart?

Previously I wasn't a big fan of this style, but it has grown on me, and I see it now as similar using "they" instead of he/she for an unspecified person. Why assume anything about the name, when you can reuse it verbatim when needed?

[dmurray]

This seems like a reasonable try but there are some problems here too. What if you're quoting someone else who called him (in speech) Mr de Zwart? Or when you find out that it's correct to use the Emperor of Japan's full name in some circumstances, but extremely insulting in another?

I think at some point you abandon looking for a general solution, and employ an expert editor who can advise you on the right style. If you're writing for a small town newspaper far away from the Netherlands and get this wrong because you don't have that expert editor, that's OK, you tried. But if you're Facebook and you have 10 million Dutch customers and you get this wrong setting the policy for the most prominent few words on the whole site, you can afford to have better standards than that.