Learn Hardcore Turkish: Kırtasiyeye uğrayınca yeni bir defter almadan edemiyorum. - Whenever I stop by the stationery shop, I can’t help buying a new notebook.

Breakdown of Kırtasiyeye uğrayınca yeni bir defter almadan edemiyorum.

Why is it kırtasiyeye and not just kırtasiye?

Because uğramak normally takes the dative case when it means to stop by / drop in at a place or person.

kırtasiye = stationery store
kırtasiye + -e = to the stationery store
because the noun ends in a vowel, Turkish inserts a buffer y:
kırtasiye + ye → kırtasiyeye

So kırtasiyeye uğramak means to stop by the stationery store.

What does uğrayınca mean here?

uğrayınca comes from uğramak + -ınca/-ince, a suffix meaning when, once, or whenever, depending on context.

So:

In this sentence, because the speaker is describing a repeated habit, it is best understood as whenever I stop by.

Why does uğrayınca imply I if there is no separate word for I?

Turkish often leaves the subject unstated if it is clear from the verb form.

Here, the I is understood from edemiyorum:

So even though uğrayınca itself does not show the person, the whole sentence is clearly about I because the main verb does.