with ds1, they never broke untill 2 secconds befor he came out, after a whole day of contractions.
ds2, they broke at 6-6:30am, started getting realy faint ones at 7pm, never realy kicked in untill the drip at the hospital arround midnight.
dd, they brok, a hour later the contractions started.
i guess it is diffrent each pregnancey..

i hope it starts up soon for you, all the best to you and your client!