You can plug the pump into a timer but you need to be sure the timer will handle the load. If you need more load capacity than the timer will handle, you can use the timer to operate a relay. If you are using standard AC power, you can use a relay with a 120 Volt coil such as Grainger stock No 5YR16 which will handle 1/2 HP at 120 Volts or 1 HP at 240 Volts.
If you are using a controller that has 24 VAC output signals:
Depending on the horsepower of your pump, you can get a relay that will fit in a small box near your controller. That relay can be actuated by the 24 Volt circuit on your controller. Grainger Stock No 5YR19 has a 24 VAC coil that will work with your controller and will operate a 1 HP pump at 240 Volts.
There is often a "Pump" contact on the controller. Connect that contact to power the coil of the relay and the pump will start when the irrigation system opens the valves. If you have only one zone, you don't need valves. You can just hook your hoses to a manifold on the discharge of the pump.
Since you will be using the pump lightly, I suggest a jet pump, 1/2 or 3/4 HP, and let it run without a pressure switch or tank. Match your sprinklers to the pump so it will operate in the range of 40 to 60 psi.
If you put a foot valve on the line into the lake, it will not lose prime.
You should install the pump at the lowest elevation possible, close to the lake.