It’s sync with tempo.
Not quantized until it’s recorded and replayed by the sequencer.
You can also just enter chords on a step, and it will play quantized.
But right now, for live playing, I can’t see other way than playing on time or using an external device.
I use my Taktile 49 keyboard’s arp to play with note start sync. Very important for me too.
How do you set it up?
A4 out > Tk49 in
Tk49 out > A4 in
A4 send clock and transport to Tk49, set to external sync. Tk49’s arp plays A4’s notes in sync.
I might be totally wrong on this, but somehow I’m starting to think that elektron does not want to give us clock-quantized arp on the A4 nor a clock-quantized retrig on the rytm. Why this would be the case, I have no idea… They hate realtime note repeat abuse? lol
Hey, actually (clock quantized) retrig on A4 would be cool as well, when you synthesize drums.
And let’s add plockable ARP in the same time, same as OT.
plockable arp on the A4 would indeed be badass, as well as LFO to arp controls like on the OT
Well, I don’t think it is on purpose, just that using arpeggios live isn’t part of a workflow they consider important/common.
I use Max to live quantize notes so my live arpeggios are always on time.
Anyway don’t give up on your expectations, my moog slim phatty did born without arp synch lock and got it on a firmware update three years later. We should borrow the dream’s technology used on Inception, then get into Cenk’s dreams to plant the idea to use live arpeggios, then wait… 
Is it possible to have the LFO in sync then? In the way that we are talking about here. If so, at least you could do “robyn type basses”
I use a trick to have live pulsate notes with the LFO always in synch.
They Key is to use trigger conditions. Set LFO to free so live notes wont re-triger the LFO, only pitch and envelopes. Then create a note on the first step and plock LFO MOD to TRG on that step, at last set trigger condition to 1ST. This way the first time the pattern rolls the LFO gets in synch, then you can play notes live either on the mini keyboard or an external controller that will alter pitch and envelopes but not the LFO.
Here it is an example on this video where the 4t note repetition is caused by the LFO and the Roli controls note pitch, amp, exp, etc.: https://youtu.be/C8waqcwEwI4?t=314
Interesting! Will try that!
About 5 1/2 years later for the tribute! 
Wow !! I had never seen that ! Indeed, you can LFO the ARP, as you can plock it !!!
Genius !!!
Damn, I don’t have an OT anymore… MK2 please arrive soon !
Yeah, abusing the OTs arp with LFOs and plocks (locked to scale too if you want) while spitting the results to MIDI, that stuff is what originally sold me on the octa 
I think this is he only snippet I’ve recorded using that so far… the whole melody is basically just messing with the LFOs on a scaled arp with a few encoder twiddles thrown in (first half of this ody demo)
This is about tamest as you can get it… with 3 LFOs and polymetry, stuff could get much much more out of hand if desired!
Long time since, but I just tried this and it works like a charm! Kind of a game changer actually!
A bit of a side note here. But on the Digitone the arpeggiator stays in perfect sync, without any workarounds. Yay.
So maybe there is hope for the A4 ??
Maybe!
Here’s an example of how I implement it. Really, killer tip there, gbravetti.
Nice!!!