Add a little horizontal space?

[Jérôme Plût]

Is there a simple way to add a little horizontal space between two
notes (actually, two time moments - preserving staff alignment) in a
score? I want to change something like this: —♩—♫—  to something like
—♩———♫— .

Does there exist an equivalent of TeX's \hskip command? I looked
through the “horizontal spacing” sections of the documentation, and
all I can find is a few words about changing the defaults, and nothing
about punctually inserting a space. (Changing the defaults is *not*
what I want: I just want a space in that one place, the defaults are
fine in all the other places!).

Thanks in advance,

-- 
        Jérôme Plût