Nicer cursor hiding/locking for Unity, including automatic alt-tab handling. Tested on 5.4+, probably fine 5.0+.

CursorManager.cs

using UnityEngine;
using System.Collections;

public class CursorManager : MonoBehaviour {
	#region Static
	#region Singleton
	/* Class is a MonoBehaviour to recieve OnApplicationFocus(bool) message
	 * If no instance already present, one will be created BEFORE scene load
	 * CursorManager placed in scene will override auto-created instance
	 * Any created instance will call DontDestroyOnLoad on itself, but still gets overridden by scene
	 * 
	 * NOTE: UI Input modules will still respond to mouse clicks. Cannot disable this without a custom input module.
	 */

	private static CursorManager __instance;
	private static CursorManager _instance {
		get {
			if (__instance == null){
				Initialise();
			}
			return __instance;
		}
	}
	[RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.BeforeSceneLoad)]
	private static void Initialise(){
		if (__instance == null){
			new GameObject("CursorManager").AddComponent<CursorManager>();
		}
	}
	#endregion

	#region API
	/// <summary>
	/// If false, cursor will always remain locked and invisible in VR
	/// </summary>
	public static bool showInVR {
		get {return _instance._showInVR;}
		set {_instance._showInVR = value;}
	}
	private static bool _vr {
		get {return UnityEngine.VR.VRSettings.enabled && !showInVR;}
	}
	/// <summary>
	/// Should be either CONFINED or LOCKED
	/// </summary>
	/// <value>The cursor mode when active.</value>
	public static CursorLockMode modeWhenActive {
		get {return _instance._modeWhenActive;}
		set {_instance._modeWhenActive = value;}
	}
	/// <summary>
	/// Stored for alt-tab
	/// </summary>
	private static bool _targetActive;
	public static bool isActive {
		get {return _targetActive;}
		private set {_targetActive = value;}
	}
	public static void SetActive(bool active){
		isActive = active;
		if (_vr) {
			// Lock and hide in VR
			Cursor.lockState = CursorLockMode.Locked;
			Cursor.visible = false;
		} else {
			Cursor.visible = isActive;
			Cursor.lockState = isActive ? modeWhenActive : CursorLockMode.Locked;
		}
	}
	#endregion
	#endregion

	#region Instance
	#region Fields
	[SerializeField][Tooltip("If false, cursor always hidden and locked in VR")]
	private bool _showInVR = false;
	[SerializeField][Tooltip("Should be either CONFINED or NONE")]
	private CursorLockMode _modeWhenActive = CursorLockMode.Confined;
	#endregion

	#region Messages
	void Awake () {
		if (__instance != null) {
			Destroy(__instance);
		}
		__instance = this;
		DontDestroyOnLoad(gameObject);
		if (_vr){
			SetActive(false);
		}
	}
	void OnDestroy(){
		if (__instance == this){
			__instance = null;
		}
	}
	private void OnApplicationFocus(bool focus){
		if (focus){
			SetActive(isActive);
		}
	}
	#endregion
	#endregion
}