Want to rotate camera horizontally around object using left and right arrow keys

I am trying to have the camera rotate around my object which is a sphere. I locked the camera onto the object using LookAt and positioning the camera in unity. I would like to be able to rotate the camera horizontally using arrow keys. Below is my script for the camera. Any suggestions?

var force : float; var jumpHeight = 8; private var isFalling = false;

function Update() { //movement var moveHorizontal : float = Input.GetAxis("Horizontal");

 var moveVertical : float = Input.GetAxis ("Vertical");
 
 var movement = new Vector3(moveHorizontal, 0.0f, moveVertical);
     
 rigidbody.AddForce (movement*force);
 
 if (Input.GetKeyDown(KeyCode.UpArrow) && isFalling == false)
 {
     rigidbody.velocity.y = jumpHeight;         //the y is y axis
 }
 isFalling = true;
        

} function OnCollisionStay ()

{

isFalling = false;

}