oql query start of day in where clause

My oql query is not coming back with full set off data due to time in the daterange.

where app .ApplicationDate >= RangeBegin($DateRange)  

How can  I use my where clause to get all for that date from the beginning of the day. something like app .ApplicationDate >= RangeBegin($DateRange).BeginOfDay

Pending the time of day i run my query the daterangeselector uses the time i run