Am I using this transistor correctly?
No, you should have the load (the lamp) in the collector circuit and the emitter of the transistor should be grounded. You should also add a resistor of about 1k Ohms in series with the base connection:
Collector: negative side of load
Base: via 1k Ohms to Arduino Pin 5
Emitter: Ground.
Positive side of load: 5V.