Explicit discourse connectives in a source language text are not always translated to comparable words or phrases in the target language. The paper provides a corpus analysis and a method for semi-automatic detection of such cases. Results show that discourse connectives are not translated into comparable forms (or even any form at all), in up to 18% of human reference translations from English to French or German. In machine translation, this happens much less frequently (up to 8% only). Work in progress aims to capture this natural implicitation of discourse connectives in current statistical machine translation models.