Camera follow.

So i got this code where the camera follows my player and i really like it, but i don't really know how to make it that it does not auto rotate, but you would be able to rotate it around player with your arrow keys (up, down, left and right) any help please, here is the code:
using UnityEngine;
using System.Collections;

public class CameraFollow : MonoBehaviour {

[SerializeField]
private float distanceAway;
[SerializeField]
private float distanceUp;
[SerializeField]
private float smooth;
[SerializeField]
private Transform follow;
private Vector3 targetPosition;

void Start ()
{
follow = GameObject.FindWithTag ("Player").transform;
}

void LateUpdate ()
{
targetPosition = follow.position + follow.up * distanceUp - follow.forward * distanceAway;
transform.position = Vector3.Lerp (transform.position, targetPosition, Time.deltaTime * smooth);
transform.LookAt (follow);
}

}

 

Maybe transform.rotateAround. Or you could parent the camera to an empty to act as an axis point at the player position and then rotate the parent.