Quote Originally Posted by Antonio1986 View Post
Based on the reasoning of the rule "tool - not tool" the following expressions should be correct:
1. он работает с энтузиазмом.
2. я жду с терпением.
3. Он пошел со своим братом.
Perfect!

Quote Originally Posted by Antonio1986 View Post
My question is: Do the Russian sometimes ommit the "c" because the following word starts with "C"
Naprimer: Он пошел с Силвертером
In writing - never!
In pronunciation, two "с" merge into a "long consonant", in careful speech it sounds distinctly due to its "length", in fast speech yes it can be hardly noticeable.

BTW, if a word starts with "с" + another consonant, then "с" is mostly replaced with "со":

с сестрой,
с солью,
с сахаром, but
со стаканом,
со светом,
со снегом,
со страусом...