Are you sure of the address? Find and use the !2C scanner program to make sure of the address. Here is code for my LCD that works.
#include <Wire.h>
#include <LCD.h>
#include <LiquidCrystal_I2C.h>
#define I2C_ADDR 0x3f // Define I2C Address where the PCF8574A is
#define BACKLIGHT_PIN 3
#define En_pin 2
#define Rw_pin 1
#define Rs_pin 0
#define D4_pin 4
#define D5_pin 5
#define D6_pin 6
#define D7_pin 7
LiquidCrystal_I2C lcd(I2C_ADDR,En_pin,Rw_pin,Rs_pin,D4_pin,D5_pin,D6_pin,D7_pin);
Your lcd.begin is for a 16 char X 2 line display.