If we're talking about an index, then unless there are a large number
of such entries (in which case one needs to define a system and follow
it) the simplest and best for most readers is to index both forms.
Yesterday I wanted to include Soraya de Chadarevian in an index.
Looking at her own publications I saw that she herself regards the "de"
as part of the surname, but it's not obvious that every reader will
assume that, so I put separate entries for "de Chadarevian, Soraya" and
for "Chadarevian, Soraya de". Adding one possibly unnecessary line to
an index is a trivial addition to the amount of space needed (unless it
pushes the whole index onto another page). Of course, if the two
entries end up within a couple of lines of other, as they well might
with "Doctor…" and "Dr...", then there is not much point in putting
both.
There are many other complications to be considered, like the fact that
French "de" and Dutch "de" are different words with different meanings,
and the various countries in which names beginning with "van" are
common (The Netherlands, Belgium, northern France, parts of the USA,
South Africa) handle them differently. Satisfying everyone is close to
impossible.
--
athel