Jansenius grants first impulses of the will are not free, because not in man's power
He does admit that some motions arise in the will that are not free for all that. These are the sudden ones that run ahead of reason's full judgment, usually called 'first-first motions'.
They come from the will without violence, yet they lack what he takes to be the chief thing in freedom. They are not in a man's power, they happen without reason's full attention, and they happen even against the will's wishes and resistance in some way, since when the will reflects on them it does not consent and would rather not have them in it at all. (On the Grace of Christ the Saviour, book 6, chapter 37.)
Latin
XXVIII. Nihilominus agnoscit motus quosdam in voluntate oriri qui propterea tamen liberi non sunt: illos, scilicet, improvisos qui plenum rationis judicium praeveniunt, & qui motus primo primi vocari solent. Quanquam enim ex voluntate sine violentia fluant, deest tamen illis quod est in libertate praecipuum ex ejus sententia, quia in hominis potestate non sunt, & fiunt sine plena rationis advertentia, & invita quodammodo ac repugnante voluntate, quia dum in motus illos reflectitur, eis non consentit, & eos omnino nollet sibi inesse. De Gratia Christi Salvatoris lib. 6. cap. 37.