Regulate 12v flow with a mosfet
That MOSFET cannot be safely driven directly by the Arduino output pin. It is specified at 10V and the Arduino (most of them) provide 5V nominal. 

A more appropriate MOSFET is the IRLZ44. 

Other than that, the circuit is fine, assuming you stay within a reasonable
current for the MOSFET (>10A is okay with the one I linked).