There's no problem driving the gate direct from the Arduino pin (perhaps a 150 ohm
resistor in series). That MOSFET works from 2.7V drive up so having the
gate at 0V and the source at 3.7V will be adequate drive. Pulling the gate voltage
above the source will simply turn it even more off.
Of course that configuration is active low from the Arduino's perspective.
A downside is that the MOSFET will be ON if the Arduino is powered down
And the LiPo is still connected.