m/anusvAra & s/visarga

[Jacob Baltuch]

Do sequences <...sk...>, <...skh...>, <...sp...> or
<...sph...> ever occur in the middle of any Sanskrit word?

Yes, I know there are sandhi rules that normally force
the conversion of <s> in such sequences to visarga or <S>
(according to the previous vowel). What I'm asking is,
are there, by any ill chance, words where, for some weird
reason, those rules did not function?

The reason I'm asking is this:

Since I do a lot of ASCII input and typing <H> and <M>
is a pain in the neck. I want to use in <s> for <H> (visarga)
(or if it comes before a sibilant, that sibilant)
and <m> for <M>. But before going ahead I want to be
fairly sure I will always be able to restaure things
from the context when I need to.

For anusvAra I am 100% sure but I'd thought I'd mention
it so as to make 101% sure.

For the visarga, of course no problem can be ex-
pected at the end of a word since <s> always turns
into visarga there. In the middle of a word the only
place I could find visarga is before <k>, <kh>, <p>
and <ph>.

Therefore I was asking: am I sure I will never find
<s> there in some weird word? (hence the first question)
since I need to know that after having changed all
my visarga to <s> I can restaure all those <s> to visarga.

Thanks for your help.