Just writing another post to prevent future people losing their mind like I have been.
The DFRobot RGB LCD Shield DFR0374 that I purchased
is unequivocally an I2C device, meaning that the description on the product page that says "Pins 4, 5, 6, 7, 8, 9 and 10 are used to interface with the LCD and Analog Pin 0 is used to read the work status of five pushbuttons" is wrong.
The shield only uses 5 pins:
5V
GND
SDA
SCL
A0 - to read the keypad presses
I have been trying to use this shield unmounted and connected by jumper wires to an Arduino Nano. The minor extra complexity is that the Nano uses pin A4 for SDA and A5 for SCL, so this wiring was successful with the example sketches in the DFRobot_RGBLCD1602 library:
Nano : Shield
5V : 5V
GND : GND
A4 : SDA
A5 : SCL
A0 : A0