I don't know about jlv2, but the Dutch frequently have a tussenvoegsel[1], an insertion between their names which is properly lowercased but is a part of the family name.
So the physicist who researched molecular stickiness is named Johannes Diderik van der Waals. His surname is "van der Waals" and a scientific reference should be cited as "van der Waals, JD", sorted alongside other surnames starting with W (either sorted at WAALS∅∅JD where ∅ is a symbol that evaluates less than any letter, or occasionally you will see them sorted at W∞VAN∅DER∅WAALS∅∅JD so that all of the tussenvoegsels end up at the end of their section, where ∞ is a symbol that evaluates greater than any letter).
It is considered formally incorrect to capitalize tussenvoegsels, except when they begin a sentence or when you precede them with an article like Mr. or Dr. You would probably want to write his name in this last-name-capitalized-first-no-commas convention as “van der KAMP Johannes Diderik;” writing ”VAN DER KAMP” looks wrong to me—but I am not sure what the French do.
Is there a Falsehoods Programmers Believe About Surnames yet? There’s famously one for names in general.
Turns out, capitalization depends on the grammatical construct. It's always capitalized at the beginning of a sentence, or to avoid ambiguity as in "Les mémoires de De Sèze". It's never capitalized when writing the full name (Jean de La Fontaine). In other constructs, it's complicated, and quite subjective...
Foreign names with particules follow the rules of the country of origin.
[1] https://fr.wikipedia.org/wiki/Particule_(onomastique)#Majusc...?
This convention comes from the bureaucracy in France, they usually write your family name in capital letter. By the way my company does the same, all our names are in capital letter in Exchange