If you need to connect a 3.3V device to a 5V system this is the module you need.  This bi-directional logic level converter module is a extremely compact package that seamlessly steps down 5V signals to 3.3V.  Conversely, it steps up 3.3V signals to 5V.  This logic level converter is designed specifically for I2C serial interface sensors and devices.  It would work perfectly to interface your 3.3V Arduino with a I2C 5V sensor, LCD, etc.