Lying is good. But advertise it when you lie. Make sure students make a note of it that you are lying.
Pedantic is bad. If you try to explain everything you will wind up explaining nothing. Let me take a simpler example. In java we have a special incantation
public static void main(String  args)
We put it in every program. It distinguishes a program. But if you start your java course explaining every part of it you will (a) confuse the juices out of them and (b) never get to the point of writing a useful program. For the beginner, it is just an incantation like
Riddikulus; // used in defence against a Boggart.
The Java code is just a "charm" for the beginner. All you need to say is that it is a "hook" for the OS to find its way into your program. Explain it later after you've taken up some of its elements for other purposes.
Beginners need a simple but coherent view of their language and system. When you simplify, work hard to keep it consistent. But it doesn't need to be complete and certainly not exhaustive.
When you are giving an "overly" simplified view, say that explicitly. Have the students mark their notes with an asterisk (or the above charm) so that they know it isn't complete. If you are explicitly asked for "the rest of the story" you have to decide whether it will help to include it (after the commercial break, of course) or to defer it or to enlighten the students out of the class context (email, say), or give a reference for those who "will not be denied."
I used to start some discussions with "I'm about to lie to you, but it will be helpful if you accept my lie for a bit". Of course I had to remember to come back an fill in the blanks later, but it might not be for a while. Complex, inter-dependent topics are like that.
tl;dr: Lie, but honestly and truthfully.
And, perhaps the most important caveat, don't lie in such a way that the student later needs to unlearn something. Lying is giving partial truths, or temporary world views, not sending students into mental blind alleys and backwaters. Withholding some facts may be necessary and valuable as is presenting an incomplete metaphor. UnLearning should never be part of learning.
I'll also note that infants learn to speak a native language without everything being explained to them before they begin. The deeper understanding comes to them only gradually and over time. We are actually conditioned by evolution to work this way.
Added in June 2022. Today's Dinosaur Comics gives a good illustration of this. Note that Ryan North, the creator of Dinosaur Comics has a masters in CS.