Lucknow University has the hostel facility, You can check the Fee for the hostel with the given below link.

http://www.lkouniv.ac.in/pdf/fee_hostels_110717.pdf

As per the eligibility to apply for BCA programme, You should be passed class 12th or equivalent examination with Mathematics Mathematics/Computer Science/Computer Application as a subject with 50% as a general category & 45% as a reserved category. You can also assure with teh given below link.

http://udrc.lkouniv.ac.in/program/Undergraduate/Eligibility?PId=62

The admission of the programme is based on the entrance test which application form generally come out in the month of April.

Good Luck!