mouse cursor disappears on screen lock

[JohnAspinall]

Upon returning from screen lock (typically, re-opening the laptop lid), and _after_ completing the password prompt, the mouse cursor is invisible.

I can restore the mouse cursor by switching away from the X console, and back again (i.e. ctrl-alt-F1, then ctrl-alt-F7).

A brief search of bug reports didn't give me a perfect match, although #1467595 matches some of the symptoms.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: xorg 1:7.7+13ubuntu3
ProcVersionSignature: Ubuntu 4.4.0-31.50-lowlatency 4.4.13
Uname: Linux 4.4.0-31-lowlatency x86_64
.tmp.unity_support_test.0:

ApportVersion: 2.20.1-0ubuntu2.1
Architecture: amd64
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: None
CurrentDesktop: XFCE
Date: Mon Aug 1 19:15:59 2016
DistUpgraded: Fresh install
DistroCodename: xenial
DistroVariant: ubuntu
ExtraDebuggingInterest: Yes
GraphicsCard:
 Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller [8086:0126] (rev 09) (prog-if 00 [VGA controller])
   Subsystem: Lenovo 2nd Generation Core Processor Family Integrated Graphics Controller [17aa:21d1]
 NVIDIA Corporation GF119M [Quadro NVS 4200M] [10de:1057] (rev a1) (prog-if 00 [VGA controller])
   Subsystem: Lenovo GF119M [Quadro NVS 4200M] [17aa:21d1]
InstallationDate: Installed on 2016-07-31 (0 days ago)
InstallationMedia: Ubuntu-Studio 16.04.1 LTS "Xenial Xerus" - Release amd64 (20160719)
LightdmDisplayLog:
 (II) AIGLX: Suspending AIGLX clients for VT switch
 (II) AIGLX: Suspending AIGLX clients for VT switch
MachineType: LENOVO 4239CTO
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.4.0-31-lowlatency root=UUID=fceabd1e-f5ef-4be2-bc1c-7241eec0c95e ro quiet splash vt.handoff=7
SourcePackage: xorg
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 05/18/2011
dmi.bios.vendor: LENOVO
dmi.bios.version: 8AET46WW (1.26 )
dmi.board.asset.tag: Not Available
dmi.board.name: 4239CTO
dmi.board.vendor: LENOVO
dmi.board.version: Not Available
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Not Available
dmi.modalias: dmi:bvnLENOVO:bvr8AET46WW(1.26):bd05/18/2011:svnLENOVO:pn4239CTO:pvrThinkPadT520:rvnLENOVO:rn4239CTO:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable:
dmi.product.name: 4239CTO
dmi.product.version: ThinkPad T520
dmi.sys.vendor: LENOVO
version.compiz: compiz 1:0.9.12.2+16.04.20160714-0ubuntu1
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.67-1ubuntu0.16.04.1
version.libgl1-mesa-dri: libgl1-mesa-dri 11.2.0-1ubuntu2
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 11.2.0-1ubuntu2
version.xserver-xorg-core: xserver-xorg-core 2:1.18.3-1ubuntu2.2
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.10.1-1ubuntu2
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.7.0-1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20160325-1ubuntu1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.12-1build2
xserver.bootTime: Sun Jul 31 19:26:38 2016
xserver.configfile: default
xserver.errors:
 Failed to load module "nvidia" (module does not exist, 0)
 Failed to load module "nvidia" (module does not exist, 0)
 NOUVEAU(G0): [XvMC] Failed to initialize extension.
xserver.logfile: /var/log/Xorg.0.log
xserver.outputs:
 product id 16561
 vendor LEN
xserver.version: 2:1.18.3-1ubuntu2.2