Dear Selva
The lintle is laid on the door level and it is act as beam. when span is less then we call it lintel. As per your quarry this all depends upon the situation at the site and design to be adopted according to loading.
If you have door or opening than you have to lay the lintel beam at 7feet height and you can lay the roof slab on the brick work, there is no harm on this kind of arragements.
If you have opening and want to take opening up to 10 feet height than lay the beam at roof level.
If you have opening and want to close it 7feet height and have any type of ventilator or any other opening above 7feet, than lay the lintel at 7feet height and you have to lay the beam with roof to cover ventilator.
These all arrangements are according to site requirement.
Secondly now in design for earth quack safety, one have to lay lintel/beam at roof level and use cement concrete ratio 1;1.5;3 instead of 1;2;4.